Refrigerator



S. B. WARD March 17, 1942.

REFRIGERATOR Filed June s, `1939 \8 Il' I lllllllllllllllllll|||||4|I|llllll INV ENT OR.

SamueZB .Wucz

ATTORNEY.

Patented Mar. 17, 1942 REFRIGERATOR Samuel B. Ward, Chester Heights,Pa., assignor to H. H. Ward Company, Chester, Pa., a corporation ofPennsylvania Application June 3, 1939, Serial No. 277,191

Claims.

My invention relates to heat exchangers and particularly to thetransmission of heat through ing with or connected to the wall, as inice cream cabinets and other refrigerators.

In accordance with my improvements, the heat conductance between thecompartment wall and the portion of the expansion tube contactingtherewith, and which is preferably spot-bonded to the wall, is augmentedby heat conductance through metallic particles, of high conductivity,such as aluminum or copper chips, making direct contact with one anotherand with the surfaces of the wall and tube, such particles beingpositioned by a heat insulating binder.

My improvementsl result in great savings ln labor and expense inattaching the tube and wall together, since it permits soldering themtogether at spaced intervalsinstead of continuously throughout thelength of the tube, and my improvements further result in increasedeitlciency due to the fact that heat maybe conducted from thecompartment wall through metallic conductors not merely to the surfaceof the tube adjacent to the wall but to the entire periphery of thetube.

Preferably, the heat conducting metallic particles or chips are mixedwith a bituminous heat insulator, such as hydrolene viz., asubstantially odorless petroleum asphalt which is fluent when hot and issolidified or rendered non-fluent by extracting heat therefrom in excessof normal room temperatures, and hence is commonly designatedthermoplastic. The bulk of the mix consists of metallic particles, withonly sufficient of the binder to hold the metallic particles togetherand to the shell and tube. This compound is applied, while plastic, tothe shellv wall to a depth sufcient to cover the tube thereon,

and the heat conducting layer thus formed has applied thereto a coatingor layer of hydrolene, or the like, devoid of metallic particles. The

' outer coating of hydrolene bonds homogeneously to the binder of theinner layer and prevents ingress of heat thereto from the outside andthe precipitation of moisture on the refrigerating unit.

My improvements are particularly applicable to an evaporating unitcomprising a metallic shell containing a compartment having therein a`longitudinally extending hollow metallic partition. Preferably, thetubing is sinuously bent so as to form closely adjacent bights or loops.

which are spot soldered or welded adjacent to their apexes to themetallic shell. The height of the tube loops engaging the external wallo f the shell is preferably less than the height of the shell so that aplurality of vertical rows of loops may be attached to the peripheralwall of the shell. To unify the temperature in different portions ofthecompartment, a row of vertical tube loops may be attached to the upperportion of the exterior of the shell throughout the bulk of theperiphery thereof: horizontally extending loops of the tube may be thenpassed longitudinally through the partition, beginning the upper portionof the partition and ending at the lower portion of the partition:vertical loops may then be attached to the remainder of the upperportion of the external periphery of the shell until the tubing loopsapproachthe inlet to the tube:

the tube may be then bent reversely upon itself Ato form a series ofvertical loops about the entire periphery of the lower portion of theexternal surface of the shell and'terminated at a connection to asuction line adjacent to the inlet from which the tubing is suppliedwith liquid refrigerant from an expansion valve.

By this arrangement of the tubing, the refrigerant has its greatest heatabsorbing capacity in passing around the upper portion ofthe shell andthereby counteracts the effect of the accumulation of the warmer portionof the air in the compartment in the upper, part thereof.

The characteristic features and advantages of my improvements willfurther appear from the following description and the accompanyingdrawing in illustration thereof.

In the drawing, Fig. 1 is a side elevation of an ice cream cabinetevaporating unit having my improvements applied thereto; Fig. 2 is a topplan view of the unit shown in Fig. l; Fig. 3 is an elevation of theright-hand end of the unit shown in Fig. l; Fig. 4 is an enlargedfragmentary detached sectional view taken on the line 4-4 of Fig. 1';Fig. 5 is an enlarged fragmentary elevation showing the spot-solderingof the apex of the bight of a loop to the conducting wall of theevaporating unit; Fig. 6 is a side elevation of the shell into aplurality of refrlgerating chambers. y y

An expansion tube 5 of copper or the like has one end connected with aliquid inlet plate 6 fixed to the front wall of the shell intermediatethe ends thereof. Sigmoldally bent sections of the tube extend along theleft half of the upper portion of the shells front wall, left end wall,back, and half of the right end wall of the shell. At the center of theright end wall of the shell, the tubing enters the top of the hollowpartition 2 and is bent back and forth therein, as shown in Fig. 7, andemerges from the central partition at the lower part of the center ofthe right end wall of the shell. From there the tubing extends upward tothe front half of the upper portion of the right end wall of the shell,and extends in sigmoidal loops along the same and along the right halfof the upper portion of the front wall of the shell. The tubing is thenbent downwardly and sigmoidal loops thereof are attached to the lowerportion of the periphery of the shell, extending from the downtake alongthe lower right front wall, lower right end wall, lower rear wall, lowerleft end wall and lower left front portion of the wall of the shell to asuction line outlet plate 8 which is preferably disposed between theliquid inlet plate 6 and the downcomer connecting the upper and lowerrows of sigmoidal loops.

Each of the vertically disposed sigmoidal loops has its apexspot-soldered to the metallic wall of the shell by a spot of metallicsolder 9 and the tube lies throughout its length in close contact withthe walls of the shell and partition.

A compound l composed of metallic particles, such as aluminum or copperchips, borings, or the like, and abinder, such as hydrolene, or thelike, is applied to the external Wall of the shell I so as to cover thetubing attached thereto. The compound should be composed of suchproportion of metallic particles and binder as will insuremetal-to-metal contact between the particles and provide heat conductingpaths between the surface of the shell i and the periphery of thetubing. A compound composed of 90 parts of metal particles by volume to10 parts of hydrolene is suitable.

The layer of metal-filled compound preferably has homogeneously bondedthereto a layer Il of heat insulating material, such as hydrolene, and

the external surface of the hydrolene layer is covered with waterproofpaper I2 which adheres thereto.

Such a shell may be housed in a suitable insulating cabinet I3.

My improvements not only improve the operation of evaporating units, butalso facilitate the manufacture of such units by effecting rapid coolingof the molten hydrolene after the application of the compound to theshell, for the metallic filler in the compound rapidly conducts the heatthereof to the shell whose inner surface provides a large cooling area.v l

Having described my invention, I claim:

1. In apparatus of the character described, the combination with ashell, `of a refrigerant coil having a rowof sigmoidally bent verticalloops around the upper portion of said shell with one end forming arefrigerant inlet and a row of sigmoidally bent vertical loops aroundthe lower portion of said shell having one end connected with an end ofsaid row first named and an end forming a refrigerant outlet.

2. In apparatus of the character described, the combination with ahollow shell of a refrigerant coll comprising a row of bent verticalloops attached to the exterior of said shell, a layer of thermoplasticmaterial containing small particles of non-ferrous metal of high thermalconductivity attached to the exterior of such shell and substantiallycovering said loops, said layer being of less thickness between saidcoils than adjacent thereto, and a layer of thermoplastic material oflow conductivity homogeneously bonded to said layer first named, saidsecond named layer having a greater thickness between said coils thanadjacent thereto.

3. A refrigerator comprising a hollow metallic shell Yhaving a partitiontherein dividing it into a plurality of compartments; expansion tubinglooped along and bonded to the upper portion of the exterior of theshell throughout the bulk of the periphery thereof, then passing throughsaid partition, and then looped along and bonded to the lower portionofthe exterior of the shell throughout the bulk of the periphery thereof;and a coating of metallic particles bonded to the exterior of said shelland tubing by a thermoplastic binder.

4. A refrigerator comprising a hollow metallic shell having convolutedtubing spot-bonded to the external wall thereof, a coating of metallicparticles bonded to the exterior of said shell and tubing by athermoplastic binder of low heat conductivity, and a coating homogeneouswith said binder and substantially devoid of metallic particles bondedto said coating first named; said last named coating being thickerbetween the convolutions of said tubing than adjacent thereto.

5. A method of forming refrigerators which comprises spot bonding a benttube ,to the external wall of a hollow metallic shell; applying to theexternal surface of the shell, to a depth sufcient to cover the tubethereon, a compound comprising metallic particles of high heatconductivity` and a binder of low heat conductivity which is fluid whenhot and solid when cold; said compound being applied while the binder ishot; applying a homogeneous coating of said' binder, while hot andsubstantially devoid of metallic particles, to said compound; andfacilitating the hardening of said binder materials by rapidlytransmitting heat therefrom through said metallic particles to said tubeand metallic shell.

' SAMUEL B. WARD.

